adding propertyproxyvalidator to web.config file

I would like to add the propertyproxyvalidator control to my web.config file so that I can avoid the tagprefix cc1. I would like to call it something else. But I don't know how to do it correctly, see below:

<add tagPrefix="entlibvalidator" namespace="Microsoft.Practices.EnterpriseLibrary.Validation.Integration.AspNet" assembly= what do I put here????????????? />